Nomenclature--The systematic Chemical Abstracts name for mitomycin C is (Shirahata et al., J. Am. Chem. Soc. 1983, 105, 7199-7200):
[1aS-(1a.beta.,8.beta.,8a.alpha.,8.beta.)]-6-amino-8-[(aminocarbonyl)oxy)me thyl]-1,1a,2,8,8a,8b-hexahydo-8a-methoxy-5-methylarizidino[2',3',3,4,]pyrro lo[1,2-a]indole-4,7-dione according to which the azirinopyrroloindole ring system is numbered as follows: ##STR1##
A trivial system of nomenclature which has found wide use in the mitomycin literature identifies the foregoing ring system including several of the characteristic substituents of the mitomycins as mitosane. ##STR2## We have chosen in the present specification to use this system and to refer to the aziridino nitrogen atom as 1a and the ring amino nitrogen atom as 7-NH.sub.2. As to the stereochemical configuration of the products of this invention, it is intended when identifying them by the root name "mitosane" or by structural formula to identify the stereochemical configuration thereof as the same as that of mitomycin C.